Yusss, you install Kage and then you work with your agent as you regularly do, it automatically captures memories from your live session like decisions, gotchas, runbook, bug fixes etc... it automatically links them to the right code blocks.
'kage propose --from-diff' is a supplementary tool that you can use to create a feature summary packet.
'kage pr check' runs validation and graph-freshness, and blocks on hard-stale memory your diff invalidated. You can run 'kage pr check' in your CI as well, that's what Kage is doing it in it's own repo.